The generation of oocytes is a complex process that begins in early embryogenesis and which culminates in the adult with the fertilization and subsequent development of a new organism. The developmental program of the oocyte requires that it expresses genes not only for its own development, but also that of the early embryo prior to zygotic genome activation. The latter process requires the storage of maternal RNAs. Recently, a novel germ cell specific gene of unknown function, called tudor domain containing 1 (TDRD1), has been cloned. Tudor domain containing proteins have been implicated in the regulation of RNA storage and metabolism, and similarly, TDRD1 may be involved in the regulation of oocyte mRNAs. The long-term objective of this proposal is to characterize this germ cell specific gene. The specific aims of this proposal are to 1) fully identify and characterize the expression of Tdrd1 in early embryonic, fetal, and adult stages of oogenesis; 2) analyze the function of TDRD1 in oogenesis by identifying the proteins with which it interacts; and 3) generate a mouse knockout model of TDRD1 in order to test the in vivo role of TDRD1 in male and female fertility. These studies will potentially lead to an understanding TDRD1 function in germ cell development, and in turn, of the process of oogenesis. A better understanding of oogenesis is necessary as we try to develop more successful treatments for human infertility.